The invention concerns a connecting rod bearing shell or bushing for internal combustion engines or a main bearing shell for bearing the crankshaft of internal combustion engines, made from a sliding bearing composite material with a metallic, preferably steel, support layer, and with a metallic sliding layer disposed thereon.
Connecting rod bearing elements, i.e. connecting rod bearing shells surrounding the crank pin of a crankshaft, and connecting rod bearing bushings which surround the piston bolt and can be pressed into the small end bearing, must meet multiple requirements. On the one hand, the connecting rod bearing shells must be durable at high sliding speeds and average loads, and the connecting rod bearing bushings must be durable at high loads and higher temperatures but slower to moderate sliding speeds. The requirements for main bearing shells in crankshafts are determined by the reduced load at these locations compared to connecting rod bearing shells and the high sliding speed at relatively moderate temperatures. Main bearing shells must also be able to compensate for misalignment of the crankshaft.
The Assignee has disclosed connecting rod bearing bushings for use in the small connecting rod eye of an engine connecting rod whose sliding layer consists of a copper zinc alloy having a relatively large zinc portion of approximately 30% by weight and 2% by weight of manganese, 2% by weight of nickel, 2% by weight of aluminium and 1.8% by weight of iron.
EP 1 158 062 A1 discloses a copper zinc aluminium wroughting material and its use for producing bearing bushings for connecting rods and pistons in internal combustion engines. The material consists of 63.5 to 66.5% by weight of copper, 2.0 to 5.4% by weight of aluminium, 4.1 to 4.9% by weight of manganese, 2.6 to 3.4% by weight of iron, 1.1 to 1.9% by weight of nickel, the rest being zinc and the usual impurities. The embodiments disclose a zinc content of 20 or 22% by weight.
DE 44 11 762 A1 discloses a sliding layer composite material wherein a copper-zinc wroughting alloy having a large zinc portion of 28 to 32% by weight is roll-bonded to a support layer of steel.
DE 198 01 074 A1 discloses a sliding layer composite material with a copper zinc alloy having a proposed ratio between α and β phase of 1.5 to 6.
CH 223 580 discloses copper zinc alloys, in particular for producing machine parts which are exposed to frictional loads, with 2 to 8% by weight of aluminium, 0.05 to 3% by weight of silicon, 0.5 to 10% by weight of manganese and 50 to 70% by weight of copper. Up to 10% by weight of lead and 0.1 to 5.0% by weight of iron, nickel and cobalt may be added to the alloy.
DE 197 28 777 C2 discloses a layered composite material having a carrier layer and a metal bearing layer, in particular made from a copper zinc alloy and with an electro-plated lead-free sliding layer on the basis of tin.
In view of the above, it is the underlying purpose of the present invention to produce a sliding layer composite material which is suitable for use as connecting rod bearing shell and also for use as connecting rod bearing bushing and main bearing shell for the crankshaft.